Scientific Forecaster Discussion

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
1222 PM CST TUE MAR 3 2015
.UPDATE...
ISSUED AT 1220 PM CST TUE MAR 3 2015
WE WILL ISSUE A WIND ADVISORY THROUGH 00Z IN THE VALLEY...GETTING
WINDS INTO CRITERIA NOW. OTHERWISE...THE FORECAST REMAINS
UNCHANGED FROM PREVIOUS UPDATE.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 320 AM CST TUE MAR 3 2015
NUMEROUS FORECAST CHALLENGES WITH MOST REVOLVING AROUND STRONG
COLD FRONT AND SNOW BAND ACROSS THE FAR SOUTH-EAST ASSOCIATED
WITH COUPLED JET STRUCTURE MAINLY DURING THE MORNING HOURS.
MODELS IN GOOD AGREEMENT THROUGH THE FORECAST PERIOD. OF MAIN
CONCERN WILL BE SNOW POTENTIAL AND BASED ON CURRENT RADAR TRENDS
WILL FOLLOW RUC/HRRR WHICH ARE PRETTY CLOSE IN DEPICTING
DEVELOPING SNOW BAND. REASON IS MESOSCALE MODELS IN THE SHORT TERM
TEND TO OUT PERFORM LARGER SCALE MODELS IN SNOW COVERAGE WHICH
WILL BE KEY TO POTENTIAL BLIZZARD CONDITIONS ACROSS THE FAR SOUTH.
SNOW BAND JUST STARTING TO GET ORGANIZED FROM SW-NE SD INTO CENTRAL
MN. EARLY GOING LOOKS LIKE OPERATIONAL MODELS MAY BE A BIT TOO FAR
NORTH WITH SNOW BAND. SO FAR BASED ON CURRENT UPSTREAM RADAR
TRENDS AND MESOSCALE MODEL SOLUTIONS PRIMARY CONCERN FOR
SIGNIFICANT BLSN/SNOWFALL WILL BE IN THE MN/ND/SD BORDER REGION
INTO ADJACENT WEST CENTRAL MN. RUC PUTS THIS AREA ON NORTHERN
FRINGE OF MAIN SNOW BAND WHILE THE HRRR A BIT FARTHER SOUTH
CLIPPING POSSIBLY GRANT COUNTY. WITH THE FARTHER NORTH RUC MAIN
ISENTROPIC LIFT AND LOWER CONDENSATION PRESSURE DEFICITS FROM 285K
SURFACE FARTHER SOUTH SUPPORTING HRRR SOLUTION. RUC THEN SHIFTS
MAIN SNOW BAND EAST OF TARGET AREA MID-LATE MORNING.
SEVERAL THINGS TO CONSIDER FOR POTENTIAL BLIZZARD ACROSS THE FAR SOUTH.
SNOW COVER FROM FROM COOPS AND VISIBLE IMAGERY SLIM TO NONE ACROSS
THE FAR SOUTH SO WILL BE RELYING ON FALLING/ACCUMULATING SNOW.
BASED ON TIMING OF COLD FRONT STRONGER WINDS WILL BE DEVELOPING
WHEN SNOW SHOULD BE WINDING DOWN. OUTPUT FROM LOCAL BLOWING SNOW
MODEL MARGINAL FOR BLIZZARD CONDITIONS WITH OVER 30KTS SUSTAINED
NECESSARY FOR BLIZZARD WITH FALLING SNOW AND NEARLY 40KTS WITH NO
SNOW. WOULD LIKE TO SEE MORE CONVINCING DATA BEFORE GOING WITH
BLIZZARD WARNING. OF COURSE ITS POSSIBLE FOR BRIEF BLIZZARD
CONDITIONS BUT THIS LOOKS TO BE A BRIEF PERIOD AND SHOULD BE AFTER
MORNING COMMUTE AND START OF SCHOOL. WITH THIS REASONING WILL
REPLACE BLIZZARD WATCH WITH ADVISORY. FARTHER NORTH AND WEST
CONFIDENCE LOWERING THAT MUCH IF ANY MEASURABLE SNOW WILL OCCUR.
WILL MAINTAIN CURRENT ADVISORY BUT MONITOR AT NEXT UPDATE PERIOD.
N AND W OF THIS AREA ISOLD SHSN ABOUT THE ONLY THING HAPPENING
BEHIND COLD FRONT AND WITH NO BLOWABLE SNOW WILL HOLD WITH CURRENT
HEADLINES. ONCE FRONT GOES THROUGH STRONG COLD ADVECTION WILL LEAD
TO MINIMAL TEMPERATURE RECOVERY.
TONIGHT WIND CHILLS WILL BE THE MAIN ISSUE. SINCE WIND CHILLS NOT
TO REACH ADVISORY CRITERIA UNTIL EVENING HELD OFF ON HEADLINES
WITH OTHER MORE IMPORTANT HEADLINES ONGOING DURING THE DAY. COLD
POOL SETTLES OVER FA LATE TONIGHT. WILL BE ENOUGH MIXING TO KEEP
TEMPERATURES FROM REALLY DROPPING BUT WILL BE SUFFICIENT FOR WIND
CHILL HEADLINES.
WEDNESDAY WILL BE COLD WITH DIMINISHING WIND DURING THE DAY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 320 AM CST TUE MAR 3 2015
SURFACE HIGH DROPS THROUGH THE FA WEDNESDAY NIGHT AND AFTER
MIDNIGHT WILL BE SEEING SOME W-SW SURFACE WIND ALONG WITH WARM
ADVECTION. EXPECT MINIMUM TEMPERATURES ALONG AND WEST OF VALLEY
PRIOR TO MIDNIGHT AND COLDEST READINGS MAINLY EAST OF THE VALLEY.
MIXING AND RESPECTABLE WARM ADVECTION WILL ALLOW FOR GOOD
TEMPERATURE RECOVERY THURSDAY BUT STILL BLO AVERAGE WITH INITIAL
COLD START.
GFS SOLE MODEL PAINTING QPF ACROSS THE NORTH WITH WEAK TROUGH
PASSAGE THURSDAY NIGHT AND KEPT FORECAST DRY. MINIMUM TEMPERATURES
WILL BE MUCH CLOSER TO AVERAGE.
FOR FRIDAY THROUGH MONDAY...WILL KEEP THE NORTHWEST FLOW ALOFT FOR
THE DURATION. HOWEVER THE FLOW DOES START TO TURN MORE WEST-NW BY
MONDAY WITH THE MODELS SHOWING THE PROMISE OF EVEN BETTER THINGS TO
COME BY MID NEXT WEEK. FIRST THINGS FIRST...MODELS STILL SHOW A WEAK
WAVE ON FRIDAY NIGHT. HOWEVER SINCE THE MAIN SFC REFLECTION LOOKS TO
REMAIN IN CANADA WILL KEEP THE DRY FORECAST. NEXT WEAK WAVE DROPS
DOWN THE NORTHWEST FLOW SAT NIGHT/SUN MORNING. ONCE AGAIN THE MAIN
SFC REFLECTION STAYS IN SOUTHERN CANADA BUT THIS TIME THE MODELS
SHOW SOME LIGHT PCPN ACROSS THE NORTH/NE FA. WILL KEEP SOME LOW
CHANCES IN THESE AREAS FOR NOW AND SEE WHAT LATER RUNS HAVE IN
STORE. 00Z GFS SHOWS ANOTHER WEAK SYSTEM SUN NIGHT/MON MORNING WHILE
THE ECMWF IS MUCH WEAKER AND FURTHER EAST. WILL KEEP THE FORECAST
DRY FOR THIS ONE. KEPT TEMPS ABOVE NORMAL THROUGH THE ENTIRE PERIOD
BUT STILL HAVE SOME UNCERTAINTY FOR FRI-SUN AS THE PREVIOUSLY
MENTIONED WAVES MOVE THROUGH. ACTUALLY HAVE A LITTLE BETTER
CONFIDENCE BY MONDAY AS THE FLOW STARTS TO TURN WEST-NW AND THE
ECMWF ESPECIALLY INDICATES WARMER 850MB TEMPS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1220 PM CST TUE MAR 3 2015
WINDS WILL GUST NEAR OR OVER 30KTS AT TIMES THROUGH THE
AFTERNOON...BEFORE GRADUALLY SUBSIDING BY THIS EVENING. A MIX OF
MVFR TO LOW VFR CEILINGS ARE EXPECTED THROUGH THE AFTERNOON...WITH
SOME CLEARING BY THIS EVENING. SOME REDUCED VISIBILITIES ARE
EXPECTED AT TIMES THIS AFTERNOON ESPECIALLY AT KTVF/KBJI...OR WITHIN
ANY BRIEF SNOW SHOWERS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR NDZ053.
WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR NDZ006>008-014>016-
024-026>030-038-039-049-052-054.
MN...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR MNZ024-
027>032-040.
WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR MNZ001>004-007.
&&
$$
UPDATE...DK
SHORT TERM...VOELKER
LONG TERM...GODON/VOELKER
AVIATION...MAKOWSKI